Measuring instrument.



E. SCHATTNER.

MEASURING INSTRUMENT.

APPLIOATION FILED AUG. 23, 1907.

912, 181 v Patented Feb. 9, 1909.

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Specification of Letters Patent.

Patented as. e, 1909.

Applicationfild August 23, 1997. Serial'NcI. $89,812:

To all whomz't may concern.-

Be it known that I, ERNEs'r'SonAT'rNEn; a subject of the King of Great Britain, residing at Ealing, England, have invented certain new'and useful Improvements in Measuring Instruments, of specification.

This invention relates to measuring 'inetru ments and more particularly to instruments for making a record of the quantities-measured.

In many kinds of measuring instruments, particularly electrical instruments, the forces available to move the pointer are small, hence the moving parts must be as light as possible and the pointer must move over the record sheet with a minimum amount of "friction, since any friction between the pointer and the. record sheet seriously impairs the accuracy-of the instrument and-injures increased operating power. Many recording instruments make a mark on a record'sheet by means of a pen, which is made as small andlight as possible, with the result that the pen requires cleaning and re-filling at frequent intervals.

The object of my invention is to provide arecording instrument which produces a clear and legible record, which reduces friction be' tween the pointer of the instrument and the record sheet to a minimum, which eliminates the necessity of cleaning and filling a pen or similar device, and a further object is to im' prove in general the construction and operation ofrecording instruments.

In carrying out my invention I provide 'a response to the variations of ener y to bemeasured, the coating is heated an thereby removed from that portion of *the record sheet immediately beneath the end of'the pointer, .whereby a mark or line, due to the lfference in appearance of the coating and the record sheet, is left as a record of the movement of the pointer. The record sheet may removed or melted'by heat. In the pre' ferred arrangement the record sheet is made of aper or other insulating material "coated wit a thin film of metal foil and known as which the following is a be of any suitable materialand the coating may be of any substance which is silver paper. This record sheet is mounted on'sultable mechanism for moving 1t at a un1- to the direction of travel of the record sheet in response to the variations of energy. A

source of electricity is connected to the ointer or electrode and also to the metallic film of the record sheet, so that when the electrode makes contact with the film a current of electricity flows and generates enough heat at the point of contact to melt the metal film whereupon the metal immediately adjacent theelectrodedisappears and the circuit through the electrode isbroken or asmall one-is formedwhich increases the resistance of said circuit. measured maintains a constant torque on the electrode and driyes it forward against a fresh metallic surface, thus the indicator arm has acom aratively free movement, as the metal walf is constantly -burned away and the indicator-can take the full range of deflection' determined by the current to be measured unimpeded by any lag due to friction. As the electrode moves back and forth over the'record sheet the metallic film is melted in a line which is a true record of the movement of the electrode and which is easily'visible on account of the difference in appearance between the metallic film and the record-sheet immediately beneath it.

invention will best be understood in connection with the accompanying drawings which are merely an illustration of one embodiment of my invention and in which Figure 1 shows an electrical recording measuring instrument constructed in accord ancewithmy invention; Fig. 2 a view of a record sheet with record made thereon; and Fig. '3 a sectional view of the record sheet showing the insulating base with the metallic film secured thereto.

In the arrangement shown in Fig. 1 the electrical measuring instrument may be of any well knownty e and as shown comprisesthe usual fie d magnet 1 and moving coil 2 pivotally mounted adjacent the field magnet and held in normal position by a helical splring 3 having one end attached to the spin e on which the coil is mounted and the other end rigid-1y secured to a sup ort or' framework 4. When no curre'nt is owing the spring 3 -holdsthe" coil 2 in its zero posi The current to be tion, but when current flows the coil turns erensr the moving coil 2 and forming an electrical against the tension of the spring 3 a distance connection between the connection 21 and depending upon the amount of current. The

current is led to the moving coil 2 through the spring 3 from a binding-post 5 mounted upon the frame or support 4. The spindle on which the coil 2 is mounted also carries a collar 6 to whichis secured a pointer or arm 7 the free end of which carries a member or electrode 8 which is moved back and forth through an-arc of a circle by the coil 2. Any other. type ofmeasuring instrument could be substituted for that shown in Fig. 1 as long as a metallic member or electrode 8 is moved over a record sheet by the instrument.

To obtain a record of the movements of the pointer or electrode 8 a support or plate 9, preferably of insulating material, is mounted adjacent the electrode and parallel to its path of movement so that the electrode 8 swings back and forth over the plate 9 but out of engagement therewith. The record sheet is ed between the electrode 8 and the plate 9 mounted upon a shelf 10 forming a art of the frame-work 11 'by a feeding mec anism of any suitable sort, shown in the drawings as a feeding cylinder 12 mounted in the frame-work 11 and driven in any suitable manner by clockwork or other suitable actuating mechanism to shift the record sheet from a roller 13 over the plate 9 to a roller 14 by means of projectionsonihe feeding roller 12 which engage perforations in the record sheet 15. As shown in Fig. 3, the referred form of record sheet consists of a carrying a metal coating 15 preferably of low melting point'and differing in appearance from the base 15 so that if by any means the coating 15 is removed the contrast in appearance between the coating andthe base exposed by the removal of the coating will be noticeable. In the preferred form of record sheet the base 15 consists of paper or other insulatingmaterial, whilerthe coating 15 is a thin film of metal foil, lead, tin, sllver or other fusible or heat sensitive conducting material The movable member or electrode 8 controls the ap lication of heat to the coating on the record s eet in any suitable manner, but preferably the heat is generated by a current of electricity flowing through the electrode and coatin The preferred arrangement for securing t e flow of current comprises a brush 16 of large surface relatively to the electrode arranged to engage the conducting surface of the record sheet 15 as the sheet is moved over the plate 9 by the feeding mechanismand connected through a lead 17 to a battery or other source of electric current 18. The source of. current is also connected to a lead 19 through a conducting finger 20 carried on the frame 4 and having one end connected through a connection 21 with a conducting collar 22 mounted' on the spindle-0f ase 15*" the arm 7 which carries the metallic member or electrode 8. With this arrangement therefor a circuit is completed from the bat- 7 tery 18, through the arm 7 and electrode 8, thence through the metallic film of the record sheet to the brush 16 and back to the battery 18. The circuit is so adjusted that the fiow of current is sufficiently great to melt instantly the thin film of metal immediately beneath the ointer or electrode 8. As soon as the film 1s melted-the molten metal is either absorbed by therecord sheet or else separates and adheres to the film on each side of the electrode, thereby removing all metal from beneath theelectrode 8 and breaking the circuit. As the electrode 8 moves back and forth over the recordsheet 15 at right angles to the direction of movement of said 8 sheet, a line is traced by the melting of the film beneath the point of the electrode and this line is clearly visible on account of the marked difference in appearance between the record sheet and the metallic film. The friction between the electrode 8 and the record sheet is reduced to a minimum since all that is necessary is that the electrode 8 be close enough to the metallic film to complete the circuit when the film immediately beneath 9 the electrode is unbroken, and this result may be obtained with a very light or even zero pressure of the electrode on the film, while the removal of the film as fast as the electrode moves over it removes most of the resistance to the movement of the electrode, so that the instrument is free from the errors caused by the pressure of a pointer on a re cording surface.

' My invention may be embodied in many other forms than that shown and described, and I therefore do not wish to be restricted to the precise form shown, but intend to cover by the appended claims all changes and modifications within the spirit and scope of my invention. 1

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. In a recording instrument, the combination with feeding means for a record sheet having a coating difie'rent from the sheet and removable therefrom by heat, of a membermovable overthe coating of said record sheet inres onse to variations of current, and means for eating the coating between said member and the record sheet.

2. In a recording instrument, the combination with a member movable in response to variations of the quantity to be measured, of means for causing a record sheet which is changed in appearance by heat to travel in contact with said member, and means for heating only that part of said record sheet which is in contact with said member.

3. In a recording instrument, the combination with a record sheet having a fusible coating, of a pointer movable over said record sheet in response to variations of the quantity to be measured and means for fusing said coating between said pointer and said record sheet.

4. In a recording instrument, the combination with an electrode and means for moving said electrode in response to variations of current, of means for moving a record sheet having a fusible conducting coating in contact with said electrode, and a source of heating current connected to the electrode and to the record sheet.

5. In combination with an electrode and means for moving said electrode in response to variations of current, of means for causing an insulating record strip with a fusible conducting film to travel with said film in contact with the electrode, and a source of current having one 'pole in electrical connection with said electrode and the other pole with said film.

6. The combination with an electrode and means for moving said electrode in response to variations of current, of means for causing an insulating record strip with a fusible conducting film to travel with said film in contact with the electrode, a brush in engagement with said film and a source of current connected to said electrode and to said brush.

7. The combination with an insulating record sheet having a thin film of fusible metal thereon, of an electrode arranged to move in response to variations of current over the film in contact therewith, and

means for connecting the electrode and the film in circuit with a source of current.

In witness whereof, I have hereunto set my hand this ninth day of August, 1907.

ERNEST SCHATTNER.

Witnesses:

F. J. SKOYLES, A. NUTTING. 

